The Bad

I found the Scarpa Booster S a notably soft and sensitive shoe for steep rock, gym climbing, and bouldering. A powerful, low-profile toe grabs well on pockets, smears, and edging. These shoes are light and as responsive as the tires on an Italian sports car. That comes at a price, though: I found the Booster S came up short as an all-around performance shoe compared to stiffer models.

FULL REVIEW

I was excited to try the Booster S, as I’ve long been a fan of the original Booster, Scarpa’s aggressive steep-rock shoe around since the latter Aughts. Interestingly, despite the name, the Booster S is actually based on the Boostic last, so is slightly different than the old Booster—size accordingly. (With flat, broad Hobbit feet, I wear a tight 41 in the Booster, but came up to 42.5 to comfortably fit the Booster S; size 42 might have been workable with a longer break-in.)

EdgingThese shoes don’t exactly “edge” per se, or at least, that’s not how it feels at first. As with so many of the newest Heinz Mariacher–designed rock boots, the emphasis is on driving force/power into the inline point of the big toe, a slightly different feel than your classic, stiffer edging platform, which distributes weight more evenly along the entire edge of the big toe. That said, the Tri-Tension Active Rand—an asymmetrical support ribbon that ties in at the third-length outsole—combined with the notable downcamber, elevates the foot to drive you right onto that power/pivot point. You “edge,” in other words, by digging, and once you get used to this style, it’s amazingly stable and powerful.

SmearingThe shoes are soft and flexible right out of the box, with stellar smearing performance.

Sensitivity/GrabbingThis is where the Booster S shines—underfoot feel. From sandstone nipples, to granite credit cards, to micro-quartz crystals embedded in a conglomerate matrix, I was able to feel and then stay put on some of the smallest footholds I’ve dared to use. The downside, of course, is that you need strong feet, but if you’re willing to put the time in and learn, the Booster S is a patient sensei. The sole is the perfect thickness for elite climbing—3.5 mm; the shoes are also exceptional, almost prehensile, at grabbing and providing traction on the super-steeps.

Hooking/ScummingThe Booster S are great for toe scums, with the same high-over-the-toebox ridged patch you find on the Boostics and Instincts, and they’re solid and versatile in heel hooks, thanks to a high, fluted-on-the-bottom heel cups. Where performance declines, however, is in torsional, camming-type moves like heel-toes, hueco cams, wide foot jams, etc.—the shoes are simply so featherweight and bendy, and toe focused, that blue-collar moves like these can feel slightly sloshy.

Fit/ClosureThe fit is a good blend of comfort and performance, and the shoes are great out of the box; expect up to a half-size of stretch. I really liked the double Velcro closure, which had broad straps and lots of mid-foot play, as well as the stretchy, perforated tongue, which conformed well to the top of my foot but stayed breathable.